The present invention relates to motor vehicles and particularly, though not exclusively to vehicles capable of performing heavy duty work functions such as loading and more particularly relates to improvements in the construction, operation and stability of such vehicles. More particularly the invention relates to a variable geometry vehicle wherein at least the wheel base can be extended to provide a counterbalance for loading which would otherwise tend to destabilise the vehicle. Whilst the present invention will be described primarily with reference to skid steer vehicles, it will be understood by persons skilled in the art that the invention is not limited to vehicles able to perform loading functions but is applicable to a wide variety of vehicles capable of performing functions other than loading.